#include <bits/stdc++.h>
#include "combo.h"
using namespace std;
typedef long long ll;
typedef map<ll, ll> mp;
typedef pair<ll, ll> pll;
typedef queue<ll> qi;
typedef vector<ll> vi;
typedef vector<bool> vb;
typedef vector <vi> vvi;
typedef vector <pll> vpl;
typedef vector <string> vs;
#define YES cout<<"YES\n"
#define Yes cout<<"Yes\n"
#define NO cout<<"NO\n"
#define No cout<<"No\n"
#define F first
#define S second
#define pb push_back
#define all(x) begin(x), end(x)
ll go() {
ll q = press("AB");
if(q >= 1) {
q = press("A");
if(q == 1) return 0;
else return 1;
} else {
q = press("X");
if(q == 1) return 2;
else return 3;
}
}
string guess_sequence(int N) {
string ans = "";
vector<char> idx = {'A', 'B', 'X', 'Y'};
ll a = go();
ans += idx[a];
for(ll i = 1; i < N; i++) {
string test;
if(idx[a] == 'A') {
test = ans + "B" + ans + "X" + ans + "Y";
} else if(idx[a] == 'B') {
test = ans + "A" + ans + "X" + ans + "Y";
} else if(idx[a] == 'X') {
test = ans + "A" + ans + "B" + ans + "Y";
} else {
test = ans + "A" + ans + "B" + ans + "X";
}
ll k = press(test);
if(k == i+1) {
if(idx[a] == 'A') ans += 'B';
else if(idx[a] == 'B') ans += 'A';
else if(idx[a] == 'X') ans += 'A';
else ans += 'A';
} else if(k == i+2) {
if(idx[a] == 'A') ans += 'X';
else if(idx[a] == 'B') ans += 'X';
else if(idx[a] == 'X') ans += 'B';
else ans += 'B';
} else {
if(idx[a] == 'A') ans += 'Y';
else if(idx[a] == 'B') ans += 'Y';
else if(idx[a] == 'X') ans += 'Y';
else ans += 'X';
}
if(i == N-1) {
if(press(ans) != N) {
ans.pop_back();
if(idx[a] == 'A') ans += (ans.back() == 'B' ? 'X' : 'Y');
else if(idx[a] == 'B') ans += (ans.back() == 'A' ? 'X' : 'Y');
else if(idx[a] == 'X') ans += (ans.back() == 'A' ? 'B' : 'Y');
else ans += (ans.back() == 'A' ? 'B' : 'X');
}
}
}
return ans;
}
